Kerry to Britain: 'We need the strongest possible E.U.'

BRUSSELS (Reuters) - U.S. Secretary of State John Kerry called on Britain on Tuesday to maintain the closest possible links with the European Union as it negotiates to leave the bloc, saying the unity of Europe was paramount for transatlantic relations.

Speaking in Brussels, Kerry sought to made the case for the European Union despite the rise of anti-EU populist parties and Britain's vote to exit. He said there could be no place for isolationist policies.

"We need the strongest possible EU, the strongest possible UK and a highly integrated, collaborative relationship between them," Kerry said in a speech.

"We should never take for granted the good achieved by the unity of Europe," he said, adding that "some people do so too quickly."

While he said that the West needed to move on from the British referendum result, he asked: "who could credibly argue that each nation, operating in a vacuum, would somehow be more efficient and effective?"